/// <summary>
        /// Creates Tekla's <see cref="Drawing.PointList"/> collection.
        /// </summary>
        /// <param name="collection">Point enumerable.</param>
        /// <returns>Tekla's PointList object.</returns>
        public static Drawing.PointList ToPointList(this IEnumerable <Geometry3d.Point> collection)
        {
            var list = new Drawing.PointList();

            foreach (var item in collection)
            {
                list.Add(item);
            }
            return(list);
        }
        /// <summary>
        /// Creates a point in average coordinates of all points in specified list.
        /// </summary>
        /// <param name="pointList">Point list to be processed.</param>
        /// <returns>Average point.</returns>
        public static Point Average(this Drawing.PointList pointList)
        {
            var array = pointList.ToArray();

            return(new Point(array.Average(p => p.X), array.Average(p => p.Y), array.Average(p => p.Z)));
        }